Preparation for New Hair Material Type (Marschner)

com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/HairData.cs

@@ -8,7 +8,14 @@ class HairData : HDTargetData
     {
         public enum MaterialType
         {
-            KajiyaKay
+            KajiyaKay,
+            Marschner
+        }
+
+        public enum ScatteringMode
+        {
+            Approximate,
+            DensityVolume
         }
 
         [SerializeField]
@@ -19,6 +26,15 @@ public MaterialType materialType
             set => m_MaterialType = value;
         }
 
+        [SerializeField]
+        ScatteringMode m_ScatteringMode;
+
+        public ScatteringMode scatteringMode
+        {
+            get => m_ScatteringMode;
+            set => m_ScatteringMode = value;
+        }
+
         [SerializeField]
         bool m_UseLightFacingNormal = false;
         public bool useLightFacingNormal

com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/HairAdvancedOptionsPropertyBlock.cs → com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/HairPropertyBlocks.cs

@@ -13,11 +13,33 @@
 
 namespace UnityEditor.Rendering.HighDefinition.ShaderGraph
 {
+    class HairSurfaceOptionPropertyBlock : SurfaceOptionPropertyBlock
+    {
+        class Styles
+        {
+            public static GUIContent materialType = new GUIContent("Material Type", "TODO");
+        }
+
+        HairData hairData;
+
+        public HairSurfaceOptionPropertyBlock(SurfaceOptionPropertyBlock.Features features, HairData hairData) : base(features)
+            => this.hairData = hairData;
+
+        protected override void CreatePropertyGUI()
+        {
+            // TODO: Un-hide me when Marschner BSDF is available.
+            // AddProperty(Styles.materialType, () => hairData.materialType, (newValue) => hairData.materialType = newValue);
+
+            base.CreatePropertyGUI();
+        }
+    }
+
     class HairAdvancedOptionsPropertyBlock : AdvancedOptionsPropertyBlock
     {
         class Styles
         {
             public static GUIContent useLightFacingNormal = new GUIContent("Use Light Facing Normal", "TODO");
+            public static GUIContent scatteringMode = new GUIContent("Scattering Mode", "");
         }
 
         HairData hairData;
@@ -30,6 +52,9 @@ protected override void CreatePropertyGUI()
 
             // Hair specific properties GUI
             AddProperty(Styles.useLightFacingNormal, () => hairData.useLightFacingNormal, (newValue) => hairData.useLightFacingNormal = newValue);
+
+            if (hairData.materialType == HairData.MaterialType.Marschner)
+                AddProperty(Styles.scatteringMode, () => hairData.scatteringMode, (newValue) => hairData.scatteringMode = newValue);
         }
     }
 }

com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/HairSubTarget.cs

@@ -33,6 +33,8 @@ sealed partial class HairSubTarget : LightingSubTarget, ILegacyTarget, IRequires
         protected override string raytracingInclude => CoreIncludes.kHairRaytracing;
         protected override FieldDescriptor subShaderField => new FieldDescriptor(kSubShader, "Hair SubShader", "");
         protected override bool requireSplitLighting => false;
+        protected override bool supportPathtracing => false;
+        protected override string pathtracingInclude => CoreIncludes.kHairPathtracing;
 
         HairData m_HairData;
 
@@ -48,23 +50,28 @@ public HairData hairData
             set => m_HairData = value;
         }
 
-        public static FieldDescriptor KajiyaKay =               new FieldDescriptor(kMaterial, "KajiyaKay", "_MATERIAL_FEATURE_HAIR_KAJIYA_KAY 1");
+        public static FieldDescriptor KajiyaKay =                new FieldDescriptor(kMaterial, "KajiyaKay", "_MATERIAL_FEATURE_HAIR_KAJIYA_KAY 1");
+        public static FieldDescriptor Marschner =                new FieldDescriptor(kMaterial, "Marschner", "_MATERIAL_FEATURE_HAIR_MARSCHNER 1");
         public static FieldDescriptor RimTransmissionIntensity = new FieldDescriptor(string.Empty, "RimTransmissionIntensity", "_RIM_TRANSMISSION_INTENSITY 1");
-        public static FieldDescriptor HairStrandDirection =     new FieldDescriptor(string.Empty, "HairStrandDirection", "_HAIR_STRAND_DIRECTION 1");
-        public static FieldDescriptor UseLightFacingNormal =    new FieldDescriptor(string.Empty, "UseLightFacingNormal", "_USE_LIGHT_FACING_NORMAL 1");
-        public static FieldDescriptor Transmittance =           new FieldDescriptor(string.Empty, "Transmittance", "_TRANSMITTANCE 1");
+        public static FieldDescriptor HairStrandDirection =      new FieldDescriptor(string.Empty, "HairStrandDirection", "_HAIR_STRAND_DIRECTION 1");
+        public static FieldDescriptor UseLightFacingNormal =     new FieldDescriptor(string.Empty, "UseLightFacingNormal", "_USE_LIGHT_FACING_NORMAL 1");
+        public static FieldDescriptor Transmittance =            new FieldDescriptor(string.Empty, "Transmittance", "_TRANSMITTANCE 1");
+        public static FieldDescriptor ScatteringDensityVolume  = new FieldDescriptor(string.Empty, "ScatteringDensityVolume", "_USE_DENSITY_VOLUME_SCATTERING 1");
 
         public override void GetFields(ref TargetFieldContext context)
         {
             base.GetFields(ref context);
 
             var descs = context.blocks.Select(x => x.descriptor);
+
             // Hair specific properties:
             context.AddField(KajiyaKay,                            hairData.materialType == HairData.MaterialType.KajiyaKay);
+            context.AddField(Marschner,                            hairData.materialType == HairData.MaterialType.Marschner);
             context.AddField(HairStrandDirection,                  descs.Contains(HDBlockFields.SurfaceDescription.HairStrandDirection) && context.pass.validPixelBlocks.Contains(HDBlockFields.SurfaceDescription.HairStrandDirection));
             context.AddField(RimTransmissionIntensity,             descs.Contains(HDBlockFields.SurfaceDescription.RimTransmissionIntensity) && context.pass.validPixelBlocks.Contains(HDBlockFields.SurfaceDescription.RimTransmissionIntensity));
             context.AddField(UseLightFacingNormal,                 hairData.useLightFacingNormal);
             context.AddField(Transmittance,                        descs.Contains(HDBlockFields.SurfaceDescription.Transmittance) && context.pass.validPixelBlocks.Contains(HDBlockFields.SurfaceDescription.Transmittance));
+            context.AddField(ScatteringDensityVolume,     hairData.scatteringMode == HairData.ScatteringMode.DensityVolume);
 
             // Misc
             context.AddField(SpecularAA,                           lightingData.specularAA &&
@@ -77,19 +84,32 @@ public override void GetActiveBlocks(ref TargetActiveBlockContext context)
             base.GetActiveBlocks(ref context);
 
             // Hair specific blocks
-            context.AddBlock(HDBlockFields.SurfaceDescription.Transmittance);
-            context.AddBlock(HDBlockFields.SurfaceDescription.RimTransmissionIntensity);
-            context.AddBlock(HDBlockFields.SurfaceDescription.HairStrandDirection);
-            context.AddBlock(HDBlockFields.SurfaceDescription.SpecularTint);
-            context.AddBlock(HDBlockFields.SurfaceDescription.SpecularShift);
-            context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySpecularTint);
-            context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySmoothness);
-            context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySpecularShift);
+            // TODO: Find common parameters between the two material types, if any.
+            if (hairData.materialType == HairData.MaterialType.KajiyaKay)
+            {
+                context.AddBlock(HDBlockFields.SurfaceDescription.Transmittance);
+                context.AddBlock(HDBlockFields.SurfaceDescription.RimTransmissionIntensity);
+                context.AddBlock(HDBlockFields.SurfaceDescription.HairStrandDirection);
+                context.AddBlock(HDBlockFields.SurfaceDescription.SpecularTint);
+                context.AddBlock(HDBlockFields.SurfaceDescription.SpecularShift);
+                context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySpecularTint);
+                context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySmoothness);
+                context.AddBlock(HDBlockFields.SurfaceDescription.SecondarySpecularShift);
+            }
+            else
+            {
+                context.AddBlock(HDBlockFields.SurfaceDescription.HairStrandDirection);
+                context.AddBlock(HDBlockFields.SurfaceDescription.LongitudinalRoughness);
+                context.AddBlock(HDBlockFields.SurfaceDescription.AzimuthalRoughness);
+                context.AddBlock(HDBlockFields.SurfaceDescription.PrimaryReflectionRoughness);
+                context.AddBlock(HDBlockFields.SurfaceDescription.RefractionIndex);
+                context.AddBlock(HDBlockFields.SurfaceDescription.CuticleAngle);
+            }
         }
 
         protected override void AddInspectorPropertyBlocks(SubTargetPropertiesGUI blockList)
         {
-            blockList.AddPropertyBlock(new SurfaceOptionPropertyBlock(SurfaceOptionPropertyBlock.Features.Lit));
+            blockList.AddPropertyBlock(new HairSurfaceOptionPropertyBlock(SurfaceOptionPropertyBlock.Features.Lit, hairData));
             blockList.AddPropertyBlock(new HairAdvancedOptionsPropertyBlock(hairData));
         }
     }

com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/ShaderPass.template.hlsl

@@ -41,6 +41,13 @@ void BuildSurfaceData(FragInputs fragInputs, inout SurfaceDescription surfaceDes
     $SurfaceDescription.SecondarySpecularTint:          surfaceData.secondarySpecularTint =         surfaceDescription.SecondarySpecularTint;
     $SurfaceDescription.SecondarySpecularShift:         surfaceData.secondarySpecularShift =        surfaceDescription.SecondarySpecularShift;
 
+    // TODO: Adopt smoothness nomenclature + factorization?
+    $SurfaceDescription.LongitudinalRoughness:          surfaceData.roughnessLongitudinal =         surfaceDescription.LongitudinalRoughness;
+    $SurfaceDescription.AzimuthalRoughness:             surfaceData.roughnessAzimuthal =            surfaceDescription.AzimuthalRoughness;
+    $SurfaceDescription.PrimaryReflectionRoughness:     surfaceData.roughnessPrimaryReflection =    surfaceDescription.PrimaryReflectionRoughness;
+    $SurfaceDescription.RefractionIndex:                surfaceData.ior =                           surfaceDescription.RefractionIndex;
+    $SurfaceDescription.CuticleAngle:                   surfaceData.cuticleAngle =                  surfaceDescription.CuticleAngle;
+
     // These static material feature allow compile time optimization
     surfaceData.materialFeatures = 0;
 
@@ -49,6 +56,10 @@ void BuildSurfaceData(FragInputs fragInputs, inout SurfaceDescription surfaceDes
         surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_HAIR_KAJIYA_KAY;
     #endif
 
+    #ifdef _MATERIAL_FEATURE_HAIR_MARSCHNER
+        surfaceData.materialFeatures |= MATERIALFEATUREFLAGS_HAIR_MARSCHNER;
+    #endif
+
     #ifdef _DOUBLESIDED_ON
         float3 doubleSidedConstants = _DoubleSidedConstants.xyz;
     #else

com.unity.render-pipelines.high-definition/Editor/Material/Hair/ShaderGraph/ShaderPassDefine.template.hlsl

@@ -1,7 +1,9 @@
 $Material.KajiyaKay:                #define _MATERIAL_FEATURE_HAIR_KAJIYA_KAY 1
+$Material.Marschner:                #define _MATERIAL_FEATURE_HAIR_MARSCHNER 1
 $UseLightFacingNormal:              #define _USE_LIGHT_FACING_NORMAL 1
 $AmbientOcclusion:                  #define _AMBIENT_OCCLUSION 1
 $SpecularOcclusionFromAO:           #define _SPECULAR_OCCLUSION_FROM_AO 1
 $SpecularOcclusionFromAOBentNormal: #define _SPECULAR_OCCLUSION_FROM_AO_BENT_NORMAL 1
 $SpecularOcclusionCustom:           #define _SPECULAR_OCCLUSION_CUSTOM 1
 $Specular.AA:                       #define _ENABLE_GEOMETRIC_SPECULAR_AA 1
+$ScatteringDensityVolume:           #define _USE_DENSITY_VOLUME_SCATTERING 1

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/HDBlockFields.cs

@@ -111,6 +111,14 @@ public struct SurfaceDescription
                 new FloatControl(0.5f), ShaderStage.Fragment);
             public static BlockFieldDescriptor SecondarySpecularShift = new BlockFieldDescriptor(SurfaceDescription.name, "SecondarySpecularShift", "Secondary Specular Shift", "SURFACEDESCRIPTION_SECONDARYSPECULARSHIFT",
                 new FloatControl(-0.1f), ShaderStage.Fragment);
+            public static BlockFieldDescriptor LongitudinalRoughness = new BlockFieldDescriptor(SurfaceDescription.name, "LongitudinalRoughness", "Longitudinal Roughness", "SURFACEDESCRIPTION_LONGITUDINALROUGHNESS",
+                new FloatControl(0.5f), ShaderStage.Fragment);
+            public static BlockFieldDescriptor AzimuthalRoughness = new BlockFieldDescriptor(SurfaceDescription.name, "AzimuthalRoughness", "Azimuthal Roughness", "SURFACEDESCRIPTION_AZIMUTHALROUGHNESS",
+                new FloatControl(0.5f), ShaderStage.Fragment);
+            public static BlockFieldDescriptor PrimaryReflectionRoughness = new BlockFieldDescriptor(SurfaceDescription.name, "PrimaryReflectionRoughness", "Primary Reflection Roughness", "SURFACEDESCRIPTION_PRIMARYREFLECTIONROUGHNESS",
+                new FloatControl(1f), ShaderStage.Fragment);
+            public static BlockFieldDescriptor CuticleAngle = new BlockFieldDescriptor(SurfaceDescription.name, "CuticleAngle", "Cuticle Angle", "SURFACEDESCRIPTION_CUTICLEANGLE",
+                new FloatControl(1.55f), ShaderStage.Fragment);
 
             // --------------------------------------------------
             // StackLit

com.unity.render-pipelines.high-definition/Editor/Material/ShaderGraph/HDTarget.cs

@@ -975,6 +975,7 @@ static class CoreIncludes
         public const string kEyeRaytracing = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Eye/EyeRaytracing.hlsl";
         public const string kStackLitRaytracing = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/StackLit/StackLitRaytracing.hlsl";
         public const string kHairRaytracing = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Hair/HairRaytracing.hlsl";
+        public const string kHairPathtracing = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/Hair/HairPathTracing.hlsl";
         public const string kRaytracingLightLoop = "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Raytracing/Shaders/RaytracingLightLoop.hlsl";
         public const string kRaytracingCommon = "Packages/com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Raytracing/Shaders/RaytracingCommon.hlsl";
         public const string kNormalBuffer = "Packages/com.unity.render-pipelines.high-definition/Runtime/Material/NormalBuffer.hlsl";

com.unity.render-pipelines.high-definition/Runtime/Material/Hair/Hair.cs

@@ -8,6 +8,7 @@ partial class Hair : RenderPipelineMaterial
         public enum MaterialFeatureFlags
         {
             HairKajiyaKay = 1 << 0,
+            HairMarschner = 1 << 1
         };
 
         //-----------------------------------------------------------------------------
@@ -70,6 +71,18 @@ public struct SurfaceData
 
             [SurfaceDataAttributes("Secondary Specular Shift")]
             public float secondarySpecularShift;
+
+            // Marschner
+            [SurfaceDataAttributes("Longitudinal Roughness")]
+            public float roughnessLongitudinal;
+            [SurfaceDataAttributes("Azimuthal Roughness")]
+            public float roughnessAzimuthal;
+            [SurfaceDataAttributes("Primary Reflection Roughness")]
+            public float roughnessPrimaryReflection;
+            [SurfaceDataAttributes("Refraction Index")]
+            public float ior;
+            [SurfaceDataAttributes("Cuticle Angle")]
+            public float cuticleAngle;
         };
 
         //-----------------------------------------------------------------------------
@@ -113,6 +126,9 @@ public struct BSDFData
             public float secondarySpecularExponent;
             public float specularShift;
             public float secondarySpecularShift;
+
+            // Marschner
+            // TODO
         };
 
 
@@ -126,23 +142,27 @@ public override void Build(HDRenderPipelineAsset hdAsset, HDRenderPipelineRuntim
         {
             PreIntegratedFGD.instance.Build(PreIntegratedFGD.FGDIndex.FGD_GGXAndDisneyDiffuse);
             LTCAreaLight.instance.Build();
+            PreIntegratedAzimuthalScattering.instance.Build();
         }
 
         public override void Cleanup()
         {
             PreIntegratedFGD.instance.Cleanup(PreIntegratedFGD.FGDIndex.FGD_GGXAndDisneyDiffuse);
             LTCAreaLight.instance.Cleanup();
+            PreIntegratedAzimuthalScattering.instance.Cleanup();
         }
 
         public override void RenderInit(CommandBuffer cmd)
         {
             PreIntegratedFGD.instance.RenderInit(PreIntegratedFGD.FGDIndex.FGD_GGXAndDisneyDiffuse, cmd);
+            PreIntegratedAzimuthalScattering.instance.RenderInit(cmd);
         }
 
         public override void Bind(CommandBuffer cmd)
         {
             PreIntegratedFGD.instance.Bind(cmd, PreIntegratedFGD.FGDIndex.FGD_GGXAndDisneyDiffuse);
             LTCAreaLight.instance.Bind(cmd);
+            PreIntegratedAzimuthalScattering.instance.Bind(cmd);
         }
     }
 }

com.unity.render-pipelines.high-definition/Runtime/Material/Hair/Hair.cs.hlsl

@@ -8,6 +8,7 @@
 // UnityEngine.Rendering.HighDefinition.Hair+MaterialFeatureFlags:  static fields
 //
 #define MATERIALFEATUREFLAGS_HAIR_KAJIYA_KAY (1)
+#define MATERIALFEATUREFLAGS_HAIR_MARSCHNER (2)
 
 //
 // UnityEngine.Rendering.HighDefinition.Hair+SurfaceData:  static fields
@@ -29,6 +30,11 @@
 #define DEBUGVIEW_HAIR_SURFACEDATA_SECONDARY_SPECULAR_TINT (1414)
 #define DEBUGVIEW_HAIR_SURFACEDATA_SPECULAR_SHIFT (1415)
 #define DEBUGVIEW_HAIR_SURFACEDATA_SECONDARY_SPECULAR_SHIFT (1416)
+#define DEBUGVIEW_HAIR_SURFACEDATA_LONGITUDINAL_ROUGHNESS (1417)
+#define DEBUGVIEW_HAIR_SURFACEDATA_AZIMUTHAL_ROUGHNESS (1418)
+#define DEBUGVIEW_HAIR_SURFACEDATA_PRIMARY_REFLECTION_ROUGHNESS (1419)
+#define DEBUGVIEW_HAIR_SURFACEDATA_REFRACTION_INDEX (1420)
+#define DEBUGVIEW_HAIR_SURFACEDATA_CUTICLE_ANGLE (1421)
 
 //
 // UnityEngine.Rendering.HighDefinition.Hair+BSDFData:  static fields
@@ -74,6 +80,11 @@ struct SurfaceData
     float3 secondarySpecularTint;
     float specularShift;
     float secondarySpecularShift;
+    float roughnessLongitudinal;
+    float roughnessAzimuthal;
+    float roughnessPrimaryReflection;
+    float ior;
+    float cuticleAngle;
 };
 
 // Generated from UnityEngine.Rendering.HighDefinition.Hair+BSDFData
@@ -162,6 +173,21 @@ void GetGeneratedSurfaceDataDebug(uint paramId, SurfaceData surfacedata, inout f
         case DEBUGVIEW_HAIR_SURFACEDATA_SECONDARY_SPECULAR_SHIFT:
             result = surfacedata.secondarySpecularShift.xxx;
             break;
+        case DEBUGVIEW_HAIR_SURFACEDATA_LONGITUDINAL_ROUGHNESS:
+            result = surfacedata.roughnessLongitudinal.xxx;
+            break;
+        case DEBUGVIEW_HAIR_SURFACEDATA_AZIMUTHAL_ROUGHNESS:
+            result = surfacedata.roughnessAzimuthal.xxx;
+            break;
+        case DEBUGVIEW_HAIR_SURFACEDATA_PRIMARY_REFLECTION_ROUGHNESS:
+            result = surfacedata.roughnessPrimaryReflection.xxx;
+            break;
+        case DEBUGVIEW_HAIR_SURFACEDATA_REFRACTION_INDEX:
+            result = surfacedata.ior.xxx;
+            break;
+        case DEBUGVIEW_HAIR_SURFACEDATA_CUTICLE_ANGLE:
+            result = surfacedata.cuticleAngle.xxx;
+            break;
     }
 }